This document contains a table of contents and sections about various BPMN concepts related to process splitting and merging:
- OR Gateway Split represents a conditional split where the conditions are independent and multiple paths can be enabled.
- Conditional Sequence Flow shows an alternative way to represent conditionally parallel flow.
- Merging Alternative Paths discusses directly merging paths that represent exclusive alternatives by looking upstream at how they were originally split.
- AND Gateway Join is used to join unconditionally parallel paths, with multiple incoming and one outgoing sequence flow.
- Multi-Merge should be avoided as it can cause downstream activities to be triggered multiple times.
- OR Gateway Join is for conditionally parallel paths, ignoring
2. TABLE OF CONTENTS
Multi-Merge, OR Gateway Join
04
Here you could describe
the topic of the section
05
OR Gateway split 01
02
Merging Alternative Paths 03
Conditionally Parallel Flow
Conditional Sequence Flow
Merging Sequence Flows
AND Gateway Join
Discriminator Pattern
3. Conditionally
Parallel Flow
OR Gateway Split :
The inclusive gateway, also called the OR
gateway, with the O symbol
inside,represents
conditional split. Like the exclusive (XOR)
gateway, each gate has a Boolean
condition,but here the conditions are
independent.
7. Merging Alternative Paths
If the paths to be merged represent exclusive alternatives, just
merge them directly (Figure 9-5,
left). In order to tell if they are exclusive alternatives, you need to
look upstream to see how
they were split in the first place.
8. AND Gateway Join
If paths are unconditionally parallel, usually you want to
join them (Figure 9-6, right). A parallel join is modeled
as an AND gateway with multiple sequence flows in and
one out.
9. Multi-Merge
Even though the parallel gateway is optional for a split, you should
not omit the gateway for the join (Figure 9-6, left). The spec
technically allows omitting the gateway – it’s called multimerge
– but it means the activity following the merge (Conduct final review)
is triggered multiple times, once for each incoming sequence
flow, and the same goes for all downstream activities.
10. OR Gateway Join
If some of the parallel paths to be joined are conditional, meaning not
enabled in every process instance, you may still join them, but you use
an OR gateway, not an AND gateway. An OR gateway join is like an
AND gateway join except that it ignores incoming sequence flows that
are not enabled for this process instance..
11. Discriminator Pattern
There is one more merging behavior worth discussing. It is called the
Discriminator pattern, and it uses the complex gateway, with the asterisk
symbol inside the diamond. A complex gateway does not necessarily
mean Discriminator. It means some user-defined behavior other than that
described by AND, OR, or XOR gateways.
